Abstract: A humidifier assembly comprises a humidifier housing having an open bottom, a rear wall opening adapted to be aligned with an opening in ducting containing air to be humidified and a front wall opening over which is removably mounted a door. A removable water collection pan closes the open bottom of the housing. The pan removably mounts a wire frame carrying an evaporator pad that extends from the pan upwardly into the housing in the path of water discharged from a spray nozzle having a solenoid controlled valve mounted on the door. Air under pressure from the warm air plenum is introduced into the housing space between the nozzle and pad to pass through the wetted pad and discharge through the rear wall opening of the housing.

Abstract: A humidifier assembly comprising a housing that is open at the rear for slidable insertion of a frame carrying a motor driven endless porous water pickup pad and a bottom mounted water reservoir pan. When the housing is mounted on a plenum or the like these and other components within the housing are not accessible for removal from the housing. A special sheet metal subassembly mounts the pad and its supporting rollers and a motor for driving one of the rollers.